Soil Aggregation, Organic Carbon Concentration, and Soil Bulk Density As Affected by Cover Crop Species in a No-Tillage System

Abstract

Soil aggregation and the distribution of total organic carbon (toc) may be affected by soil tillage and cover crops. the objective of this study was to determine the effects of crop rotation with cover crops on soil aggregation, toc concentration in the soil aggregate fractions, and soil bulk density under a no-tillage system (NtS) and conventional tillage system (ctS, one plowing and two disking). this was a three-year study with cover crop/rice/cover crop/rice rotations in the brazilian cerrado. A randomized block experimental design with six treatments and three replications was used. the cover crops (treatments) were: fallow, Panicum maximum, Brachiaria ruziziensis, Brachiaria brizantha, and millet (Pennisetum glaucum). An additional treatment, fallow plus ctS, was included as a control. Soil samples were collected at the depths of 0.00-0.05 m, 0.05-0.10 m, and 0.10-0.20 m after the second rice harvest. the treatments under the NtS led to greater stability in the soil aggregates (ranging from 86.33 to 95.37 %) than fallow plus ctS (ranging from 74.62 to 85.94 %). fallow plus ctS showed the highest number of aggregates smaller than 2 mm. the cover crops affected soil bulk density differently, and the millet treatment in the NtS had the lowest values. the cover crops without incorporation provided the greatest accumulation of toc in the soil surface layers. the toc concentration was positively correlated with the aggregate stability index in all layers and negatively correlated with bulk density in the 0.00-0.10 m layer.

Water-Stable Aggregates and Associated Carbon in a Subtropical Rice Soil Under Variable Tillage

“…Generally, a more rapid loss of SOC may occur from macroaggregates than from microaggregates (Eynard et al, 2005). The SOC change under agricultural management may owe to the aggregate stability index (Nascente et al, 2015). Thus, soil aggregated fractionation has been widely applied to evaluate the SOC stability under contrasting tillage systems.…”

Evolution of soil organic carbon during a chronosequence of transformation from cacao (Theobroma cacao l.) plantation to grassland

“…In this sense, a change in soil humic quality is not detectable since no significant variation in the soil C/N ratio is observed (Table 2). Nascente, Yuncong & Costa (2015), found that SOM concentration was negatively correlated with ρb in the surface soil horizon (0-10 cm), which are thought to contribute to a higher concentration of SOM with a lower ρ b .…”

Effect of Cover Crops on Soil Attributes, Plant Nutrition, and Irrigated Tropical Rice Yield

“…Rice is a dietary staple for half of the world's population (BELLON et al, 2006;KUMAR;LADHA, 2011;CRUSCIOL;COBUCCI, 2013). In Brazil, rice is cultivated in two distinct ecosystems: (a) irrigated flood plain (IFP) and (b) uplands.…”

“…These cultivation practices may also decrease fertilizer requirements via nutrient release from cover crop straw (VERNETTI JÚNIOR; GOMES; SCHUCH, 2009;NASCENTE et al, 2014). Nascente and Crusciol (2015) reported that the use of cover crops contributed to the increase in soil organic matter content. Cover plants can also significantly affect soil N and improve the crop development environment (NASCENTE et al, 2016).…”